Question

I have a JPanel on which I’ve dynamically added quite a few JButtons. All of this is working perfectly. Later on in my program execution, I need to refer back to these buttons and pull out the button text. I’m having trouble figuring out how to refer back to them.

When I created each button, I gave it a unique name. Let’s say this is the code where I created the button:

public void createButton(Container parent, String btnName) {
   JButton btn = new JButton("xyz");
   btn.setName(btnName);
   btn.addActionListner(new ActionListner() {
      //code
   }
   parent.add(btn);
 }

In another method, I’m trying to retrieve the label on the button since it may have changed at run time. Do I need to keep an array of these buttons as they are created? Or is there a way that I can refer back to them directly?

This is what I was working on, but it’s stupid. Can anyone suggest a correct approach?

public String getBtnLabel(String btnName) {
   JButton btn = (JButton) btnName;
   return btn.getText();
}

If the answer is that I just need to create the array and then iterate over it, that’s fine. Just looking for other options.

Answer 1

You need to use a Map<String, JButton> so when you create your dynamic buttons you give them some sort of unqiue name:

//somewhere at the top of your class
private final Map<String, JButton> myButtonMap = new HashMap<>();

public void createButton(Container parent, String btnName) {
   JButton btn = new JButton("xyz");
   btn.setName(btnName);
   btn.addActionListner(new ActionListner() {
      //code
   }
   parent.add(btn);
   myButtonMap.put(btnName, btn);
 }

And then simply get from the map

public String getBtnLabel(String btnName) {       
   return myButtonMap.get(btnName).getText();
}

This will obviously throw an NPE if the button isn’t defined…
Also you will need to delete from your map when you’re done with it otherwise you’re asking for a memory leak…